This study will develop new data and methods for linking physician practice behavior to characteristics of the physician, his or her practice, and the managed care environment. Economic and financial models will be estimated to examine how physician behavior is affected by: 1) financial and non-financial incentives facing the physician and his/her practice, 2) characteristics of the practice and competitive environment, 3) characteristics of patients, and 4) physician awareness and knowledge of incentives put in place by managed care organizations (MCOs). Physician behavior will include: 1) referral patterns; 2) scope of practice; 3) productivity; 5) provision of charity care; and 6) physician satisfaction. This research has five tasks and will be carried out over 3 years. Task 1: Qualitative fieldwork. Interviews (150) with state-level key informants, physicians and practice-level decision-makers will: i) identify types of financial and non-financial incentives existing at the level of the physician and the practice; ii) develop an organizational framework for studying the relationships between physician practices, MCOs, and intermediaries, iii) refine terminology and definitions for survey use. Task 2: Linked survey of physicians and practices: 2000 physicians and 2000 practice-level decision-makers in 5 states to gather data on: 1) the structure of financial incentives, administrative rules/clinical guidelines at the individual physician and the practice level, 2) physician's practice styles, 3) practice structure, finance and profitability; 4) physician knowledge of financial incentives and rules. Task 3: Data analysis/model estimation: Describe the extent and prevalence of financial and non-financial incentives that impact the physician and the practice. Estimate empirical models to test hypotheses about: 1) factors determining the use/extent of financial incentives and guidelines; 2) when incentives/rules are applied to physicians vs. practices; 3) the impact incentives/rules at physician and practice level on physician behavior. Task 4: Subgroup analyses: Examine differences in patterns of risk bearing and managed care contracting between: 1) urban and rural areas; and 2) practices serving the uninsured/underinsured/publically- insured versus those with commercially insured patients and evaluate potential barriers to expanding risk contracting under Medicaid and in rural communities. Task 5: Dissemination and feedback: Post-survey focus groups of policy makers and providers will assist in interpretation of results. Policy briefings will disseminate results.